package com.hmall.service.Impl;

import com.alibaba.fastjson.JSON;
import com.hmall.common.dto.PageDTO;
import com.hmall.pojo.ItemDoc;
import com.hmall.pojo.RequestParams;
import com.hmall.service.SearchService;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.functionscore.FunctionScoreQueryBuilder;
import org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.sort.SortOrder;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.SuggestBuilder;
import org.elasticsearch.search.suggest.SuggestBuilders;
import org.elasticsearch.search.suggest.completion.CompletionSuggestion;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
public class SearchServiceImpl implements SearchService {
    @Autowired
    private RestHighLevelClient client;

    /**
     * 自动补全
     * @param prefix
     * @return
     */
    @Override
    public List<String> getSuggestions(String prefix) {
        try {
            // 1.准备Request
            SearchRequest request = new SearchRequest("hmall");
            // 2.准备DSL
            request.source().suggest(new SuggestBuilder().addSuggestion(
                    "suggestions",
                    SuggestBuilders.completionSuggestion("suggestion")
                            .prefix(prefix)
                            .skipDuplicates(true)
                            .size(10)
            ));
            // 3.发起请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            // 4.解析结果
            Suggest suggest = response.getSuggest();
            // 4.1.根据补全查询名称，获取补全结果
            CompletionSuggestion suggestions = suggest.getSuggestion("suggestions");
            // 4.2.获取options
            List<CompletionSuggestion.Entry.Option> options = suggestions.getOptions();
            // 4.3.遍历
            List<String> list = new ArrayList<>(options.size());
            for (CompletionSuggestion.Entry.Option option : options) {
                String text = option.getText().toString();
                list.add(text);
            }
            return list;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 聚合
     * @param params
     * @return
     */
    @Override
    public Map<String, List<String>> getFilters(RequestParams params) {
        try {
            // 1.准备Request
            SearchRequest request = new SearchRequest("hmall");
            // 2.准备DSL
            // 2.1.query

            request.source().size(0);
            // 2.3.聚合
            request.source().aggregation(AggregationBuilders
                    .terms("categoryAgg")
                    .field("category")
                    .size(100)
            );

            request.source().aggregation(AggregationBuilders
                    .terms("brandAgg")
                    .field("brand")
                    .size(100)
            );

            // 3.发出请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            // 4.解析结果
            Map<String, List<String>> result = new HashMap<>();
            Aggregations aggregations = response.getAggregations();
            // 4.1.根据品牌名称，获取品牌结果
            List<String> brandList = getAggByName(aggregations, "brandAgg");
            result.put("品牌", brandList);
            // 4.2.根据品牌名称，获取品牌结果
            List<String> cityList = getAggByName(aggregations, "categoryAgg");
            result.put("分类", cityList);
            return result;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private List<String> getAggByName(Aggregations aggregations, String name) {
        Terms brandTerms = aggregations.get(name);
        List<? extends Terms.Bucket> buckets = brandTerms.getBuckets();
        ArrayList<String> list = new ArrayList<>();
        for (Terms.Bucket bucket : buckets) {
            String key = bucket.getKeyAsString();
            list.add(key);
        }
        return list;
    }


    @Override
    public PageDTO<ItemDoc> search(RequestParams params) {
        try {
            // 1.准备Request
            SearchRequest request = new SearchRequest("hmall");

            buildBasicQuery(params, request);
            //分页查询
            int page = params.getPage();
            int size = params.getSize();
            request.source().from((page - 1) * size).size(size);
            if("sold".equals(params.getSortBy())){
                request.source().sort("sold", SortOrder.ASC);
            }
            //价格排序升序
            if ("price".equals(params.getSortBy())){
                request.source().sort("price",SortOrder.ASC);
            }
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);

            return handleResponse(response);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private PageDTO<ItemDoc> handleResponse(SearchResponse response) {
        SearchHits hits = response.getHits();
        long totals = hits.getTotalHits().value;
        SearchHit[] hits1 = hits.getHits();
        ArrayList<ItemDoc> itemDocs = new ArrayList<>();
        for (SearchHit hit : hits1) {
            String sourceAsString = hit.getSourceAsString();
            ItemDoc itemDoc = JSON.parseObject(sourceAsString, ItemDoc.class);
            itemDocs.add(itemDoc);

        }
        return new PageDTO<ItemDoc>(totals,itemDocs);
    }

    private void buildBasicQuery(RequestParams params, SearchRequest request) {
        // 1.构建BooleanQuery
        BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
        // 2.关键字搜索
        String key = params.getKey();
        if (key == null || "".equals(key)) {
            boolQuery.must(QueryBuilders.matchAllQuery());
        } else {
            boolQuery.must(QueryBuilders.matchQuery("all", key));
        }
        // 4.品牌条件
        if (params.getBrand() != null && !params.getBrand().equals("")) {
            boolQuery.filter(QueryBuilders.termQuery("brand", params.getBrand()));
        }
        if (params.getCategory() != null && !params.getCategory().equals("")) {
            boolQuery.filter(QueryBuilders.termQuery("Category", params.getCategory()));
        }
        //价格
        if (params.getMinPrice() != null && params.getMaxPrice() != null) {
            boolQuery.filter(QueryBuilders
                    .rangeQuery("price")
                    .gte(params.getMinPrice())
                    .lte(params.getMaxPrice())
            );
        }
        // 2.算分控制
        FunctionScoreQueryBuilder functionScoreQuery =
                QueryBuilders.functionScoreQuery(
                        // 原始查询，相关性算分的查询
                        boolQuery,
                        // function score的数组
                        new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
                                // 其中的一个function score 元素
                                new FunctionScoreQueryBuilder.FilterFunctionBuilder(
                                        // 过滤条件
                                        QueryBuilders.termQuery("isAD", true),
                                        // 算分函数
                                        ScoreFunctionBuilders.weightFactorFunction(20)
                                )
                        });
        // 7.放入source
        request.source().query(functionScoreQuery);
    }
}
